loop

noun

1. A length of thread, line or rope that is doubled over to make an opening.
2. The opening so formed.
3. A shape produced by a curve that bends around and crosses itself.

   “Arches, loops, and whorls are patterns found in fingerprints.”

4. A process that returns to its beginning and then repeats itself in the same sequence.

   “feedback loop”

   “time loop”

   “An online feed that constantly “refills” manipulates the brain’s dopaminergic reward system in a similar way. These powerful dopamine-driven loops of endless “seeking” can become addictive.”

5. A ring road or beltway.
6. An endless strip of tape or film allowing continuous repetition.

   “He can hang out in the back room of the local adult bookstore […] and hope for a stand-up blow-job through the glory hole in the partition of the two booths that show gay loops.”

7. A complete circuit for an electric current.
8. A programmed sequence of instructions that is repeated until or while a particular condition is satisfied.
9. An edge that begins and ends on the same vertex.
10. A path that starts and ends at the same point.
11. A bus or rail route, walking route, etc. that starts and ends at the same point.
12. A place at a terminus where trains or trams can turn round and go back the other way without having to reverse; a balloon loop, turning loop, or reversing loop.

    “In 1908 the line was extended to a station called Wood Lane, which was built on a terminal track loop so that trains could turn round and go back the other way, [...]”

13. A passing loop.

    “Basingstoke-Exeter will test this. From Salisbury westwards, it's largely single-track since British Rail downgraded it in 1967. There's a ten-mile loop between Templecombe and Yeovil, as well as shorter loops at Chard, Axminster and Honiton.”

14. A quasigroup with an identity element.
15. A loop-shaped intrauterine device.
16. An aerobatic maneuver in which an aircraft flies a circular path in a vertical plane.
17. A small, narrow opening; a loophole.

    “And stop all sight-holes, every loop from whence / The eye of Reason may pry in upon us.”

18. (alt-of, alternative)Alternative form of loup (“mass of iron”).
19. A flexible region in a protein's secondary structure.
20. (Canada, US, dated)A sports league

    “Arellano formerly cavorted for the Galicias in the fast-paced National-American Soccer loop.”

21. The curved path of the ball bowled by a spin bowler.
22. (abbreviation, acronym, alt-of)Acronym of loss of offsite power.

verb

1. (transitive)To form something into a loop.
2. (transitive)To fasten or encircle something with a loop.
3. (transitive)To fly an aircraft in a loop.
4. (transitive)To move something in a loop.
5. (transitive)To play something (such as a song or video) in a loop.
6. (transitive)To join electrical components to complete a circuit.
7. (transitive)To duplicate the route of a pipeline.
8. (transitive)To create an error in a computer program so that it runs in an endless loop and the computer freezes up.
9. (intransitive)To form a loop.
10. (intransitive)To move in a loop.

    “The program loops until the user presses a key.”

    “The outstanding Tom Palmer won a line-out and then charged into the heart of the Welsh defence, scrum-half Ben Youngs moved the ball swiftly right and Cueto's looping pass saw Ashton benefit from a huge overlap to again run in untouched.”

11. To place in a loop.

    “It found that trains often looped on their journey emit 14% to 20% more NOx and particulates than non-stop services.”

12. (ambitransitive)To have the teacher progress through multiple school years with the same students.

    “Tolland Middle School in Connecticut where close to four hundred middle school students participated in looping, students from looped classroom structures scored much higher than students from prior years without the looped structure on standardized tests in mathematics and writing.”

name

1. A surname.
2. (informal, singular)The City Loop.

   “Does this train go through the Loop?”